Isaac Ray, the outstanding psychiatrist of 19th-century America, was responsible for establishing legal psychiatry as a separate discipline with its own skills, body of knowledge, and goals. Ray also was one of the "Original Thirteen" founders of the Association of Medical Superintendents of American Institutions for the Insane (AMSAII), later the American Psychiatric Association (APA). An active reformer, Ray was dedicated to implementing the care, treatment, and protection of the insane by the medical profession and society. Concurrently, he demanded the accordance of just respect for the needs of the families of the insane and their communities. Isaac Ray's persisting philosophical orientation was the responsible application of humane reason and knowledge to psychiatry, law, and social policy. The goals of this biography include an evaluation of Ray's role in the development of American psychiatry, as well as the integration of a traditional biographic approach with a historical reconstruction of personality dynamics, the internal history of 19th-century American psychiatry, and its social history.